Process for removing carbon from tubes



w. 1'. DAVIS Er A;

March 14, 1933. v

PROCESS FOR REMOVING CARBON FROM TUBES Filed De. l2, 1950 s .m ad

. INVENTORS:

xf- BYM-@av -zzb, ATTORNEYS.

Patented Mer. les 1333 PATNT @FFHQ YVr. nanas, or sournearn, arm ones n. nennt, or aan raan'oreco, enamorarme, essrenons 'ro rar. emma am raonuo'rs contrarre', .a contro FUEL EEEELQWNG- CARBN FRQE TUBES .application nle. December 12, 1930. Serial rTo. 591,982.

This invention relates to a method for removing combustible and other deposits from the interior ot tubesand especially in connection with the removal of the so-called petroleum coke from the interior of the tubes ot petroleum cracking stills and other tubes wherein petroleum oils are subjected to heat.

An object of our invention is to devise a method and apparatus in which the combusf l@ tible deposit is removed rapidly and economically and whereby any portions detached from the interior of the tube will be blown from the tube. Other objects of our invention will be evident fromP the followingv il@ speciiication having reference to the accompanying drawing in which f Fig. 1 is a longitudinal section of a device constructed in accordance with our invention, the section being taken on line l-l of Fig. 2 is a section taken on the line H-ll of Fig. l; and

Fig. 3 is a longitudinal section showing a modified form of our invention.

lt is well known that during the operation of oil cracking stills acarbonaceous deposit, called petroleum coke, is formed on the interior` of the parts. Heretoore, it has been customary to remove this by chipping or oth- .3@ er mechanical means, it being believed that the burning of this deposit in the presence of oxygen would produce such temperatures as to damage the walls of the oil cracking device. In the copending application of William T. Davis, .Serial No. 465,242, led July 1, 1930 there is disclosed a method and apparatus for the removal of these deposits in the presence oit oxygen. The method and apparatus there disclosed, while adapted to members of va-y 40 rious shapes, is particularly adapted to members of irregular shape. In the present application we disclose a method and apparatus particularlyadapted for straight tubes.

ln the embodiment Lof our invention shown in the'accompanying drawing we employ a head1@ which is preferably of copper, although other materials may be used. @ne end of the head has an outwardly Haring opening 11 communicating through a threaded opening 12 with an interior chamber 13. A. u@ plurality of openings 14C are also provided forming communication between the daring opening 11 and the central chamber 13. A head plug 15 is disposed within the aring opening in the head, engaging lthe threaded portion 12. rlhis head plug is provided with a plurality of centering plugs 16 whereby a conical nozzle if formed between the head and the head plug. Should we so desire we may provide an'aniiular groove 17 for assisting in t@ the distribution of oxygen from the holes 14 to the discharge space 'between the head and the head plug. A@ pipe or tube 21 extends from the threadedtportion 12 of the head and is of a suitable length to permit the inser- 6&5l

tion of the head within the tube to be cleaned for a suliicient distance to insure the complete removal of the coke therefrom. The pipe 21 is threaded at 22 tov receive a packing nut 23 and also to receive a suitable connection 24 70 to a supply of compressed air. A ring 25 is brazed or otherwise secured to the pipe 21 to cooperate with the packing nut 23 to compress suitable packing 26 therebetween to form a tight joint. 76

Should we so desire we may provide a retaining ring 29, which is brazed or otherwise secured to thepipe 21. Set screws 30 extend through the head 10 and engage the retaining ring 29. Howeverv this is not absolutely necessary, as good results are obtained when the retaining ring is omitted and the threaded portion of the head extended, as shown in Fig. 3.

The rear end of the head is threaded at 31 85 to secure a bushing 32. A pipe 33 of larger diameter than the pipe, 21 is secured to the bushing 32. This pipe 33 is provided with means for admitting oxygen to the space between the two pipes. Such a means may consist of an elbow 34 having a nipple 35 for a connection to a source of oxygen.

It will be observed that the oxygen is supplied at 35 and passes along the space between the pipes 21 and 33, through the chamber 13, thence through the opening 14 and the annular groove 17 to the diverging space be.- tween the head 10 and the head plug 16. The oxygen will impinge on the coke adhering to the inner walls of the still tube. Compressed air is supplied through the pipe 21 and an opening 27 in the head plug. rlhe head plug may be provided with openings 18 for coaction with a wrench or spanner.

The operation of our device is as follows:

Combustible material, as oily waste, is placed in one end or" the tube to be cleaned and is ignited. The oxygen is turned on and the torch inserted in the tube after which compressedv air is turned on. The oxygen impinges on the coke adhering to the inner walls and this oxygen jet causes a rapid burning and splitting-oil of the coke. The compressed air blast blows the split-oit unburned coke out of the tube. The compressed air also supplies additional oxygen to complete the combustion of the carbon monoxide formed by the burning of the carbon in thel presence of the oxygen, and may also partially or completely oxidize, additional coke ahead of the primary combustion. The rate of supply of oxygen and air should be so controlled that the combustion of carbon monoxide to carbon dioxide will take place principally inside the tube ahead of the torch head. The additional heat generated by the combustion of the carbonmonoxide greatly expedites the removal of the coke ahead of the torch and we have found it necessary to advance the torch into the tube foronly a portion of its entire length in order to secure practically complete loosening up and removing of the carbon ldeposit throughout the entire tube.

We claim:

1. Method of burning combustible deposits from the interior of a tube which comprises bringing the combustible deposit to a kindling temperature, delivering oxygen obliquely against the deposit on the Walls of the tube and delivering an oxygen containing gas axially of the tube and in'the same general direction in regard to the length of the tube as the Obliquely delivered gas.

2. Method of burning combustible deposits from the interior of a tube which comprises igniting said deposit, delivering oxygenk obliquely against the deposit, whereby the deposit is oxidized in part to carbon monoxide, and delivering oxygen containingv gas axially of the tube, whereby the carbon monoxide is oxidized to carbon dioxide with accompanying liberation of heat.

3. Method of burning combustible deposits from the interior of a tube which comprises ture.

CHARLES E. RHEN.

ln'testixnony whereof, afdix my signature.

WLLAM T. DAVIS. 

